Releasing clamp



Nov. 14, 1933. MOORE, JR 1,935,573

RELEASING CLAMP Filed Nov. 192s Sfewarf Moon Jr Patented Nov. 14, 1933 units!) STATES PATENT OFFICE RELEASING CLAMP Stewart L. Moore, Jr., Baltimore, Md., assignor to Locke Insulator Corporation, Baltimore, Md., a corporation of Maryland 7 Application November 7, 1928. Serial No. 317,856

4 Claims. (01. 24831) grip upon the conductor and permit the latter to slide through in the. event that an excessive strain occurs on the line at one sideof the clamp.

It is well known that it iscustomary to support, conductors by means of clamps at the lower ends ofrstrings of insulators, such. strings being suspended from steeltowers or other equivalent supports. In the event that :a greater strain comes-upon thei-conductor on one side of the tower than on the other, the string of insulators will move out ,of their normalsubstantially'vertical position, resulting in probable severe damage to the insulators and possible upsetting of the tower. This dangerous condition is particularly noticeable on lines where there is an extremely long span between successive towers. The excessive strain referred to may sometimes be the result of high winds but is generally caused by an accumulationof sleet orice upon the con.- ductor. An'additional contingency is: breakage of the conductor. It is obvious that in the event of a break substantially the entire weight of the conductor throughout a span comes upon one string of insulators. g

It is with the-above facts in view that I have devised the presentinvention which has for a more specific object the provision, of a clamp which will hold the conductor firmly under normal circumstances, or even under slightly abnormal circumstances, but which will automatically release in the event of breakage of the conductor or the occurrence of any other unusual and unequalized strain. a

An important object of the invention is to provide a clamp for this purpose of such formation that it will becapable of regripping the conductor after the conductor has been released and has slid through a plurality of clamps at a series of towers until the strain has been substantially equalized.

Still another object of the invention is to provide a clamp embodying .a resilient or spring clamping member positively forced into engagement with the conductor; it being a feature that the thickness or gauge of the material from which the spring clamping member is formed provides means whereby the degree of holding action may be regulated so as to permit or insure release of the clamping action upon the occurrence of a certain definite predetermined pull or strain, this feature rendering it possible to make use of a single type and size of clamp, with a selectively usable movable and removable clamping member,

' upon different installations.

' Another object is to provide a clamp having means whereby the relatively movable clamping member will be prevented from actual separation or disengagement from the main body or relatively fixed clamping member, dropping down and probable loss being thereby avoided,

An additional object is to provide a clamp of this character which will be simple and inexpensive to manufacture, easy to install, positive in action, ,eflicient and durable in service, and a general improvement in the art;

To the attainment of the foregoing and other objects and advantages, the invention preferably consists in the details of construction and the arrangement and combination of parts to be hereinafter more fully described and claimed, and illustrated in the accompanying drawing in which: I 1

Figure 1 is a side elevation of the clamp. in position upon a conductor,

Figure 2 is a vertical longitudinal section through the main body orrelatively stationary member,

Figure 3 is an end elevation withlthe. conductor in section, and

I Figure 4 is a central vertical cross section, the

View being taken on the line 44 of Figure 1.

Referring more particularly to the drawing .1 have shown the clamp as comprising a main body or relatively stationary member 1,- a relatively' elongated stirrup-like form. In other words this member may very well be U-shaped in vertical cross section, thus providing spaced sides 5 connected by a seat 6 which preferably conforms to the curvature of theconductor'to be held. The ends of the seat portion are preferably flared or-curved downwardly as at 7 to avoid contact of the-edges with the conductor 8. It is also preferable that the sides 5'be formed-with openings 9-which need not, however, have the specific shape disclosed. i

r The movable clamping member 2 is preferably of. sheet metal construction andmay'be longitudinally bowed upwardlyat itscenter as shown in Figure 1 for cooperation with a cam extension 10, or its equivalent, formed on or carried by the suspension member 3. It is preferable that the ends of the member 2 curve upwardly away from the conductor 8 to prevent edge contact therewith. In order to prevent any longitudinal shifting of the member 2 with respect to the main member 1, the former is shown as having lateral projections 11 fitting somewhat loose-- ly within the openings 9 though it is apparent that some other detailed construction could be used instead. A very convenient structure is that the entire device be formed of sheet metal though I do not care to be limited in this respect as the invention is of greater scope. It is very likely that if the body member or supporting stirrup be formed of sheet metal the clamping member may be rigid. The point is that there is a reaction between the body or stirrup and the clamping member and by making one or the other yieldable to a limited extent certain advantages will enure,

The bolt l above referred to provides an extremely simple means for connecting the suspension member 3 with the body member 1, this bolt or pin simply passing through a hole 12 in the suspension member and seating within the upper ends of the openings 9. In the present instance this element 4 is shown as a pin equipped with a cotter 13 to prevent withdrawal though it is quite apparent that a bolt and nut may be used if preferred. Aside from the provision of the cam projection 10 the specific construction of the suspension member 3 is of little importance though it is shown as of clevis formation and provided in its upper end with holes i l to permit connection, by a belt or the like, with a suspension element attached directly, or through some intermediate means, to the lower end of a string of insulators, not shown.

In effecting installation, it is clear that the main member 1 is engaged beneath the conductor 8, subsequently to which the relatively movable member 2 is inserted within it so as to lie on top of the conductor, it being easily possible to cant or tilt the member 2 to bring the projections 11 into the openings 9. Regardless of whether the suspension member 3 is connected with the string of insulators prior or subsequent to its connection with the clamp, it should be plain that to complete the assembly the suspension member 3 should be inclined from the vertical so that the cam projection 10 will not engage upon the member 2. The hole 12 must be lined upwith the openings 9 so that the pin or bolt 4 may be inserted and cottered. When weight is then permitted to come upon the as sembly, the suspension member 3 will assume a vertical position with the cam projection 10 contacting firmly with and depressing the center of the clamping member 2 so that this member will grip the conductor firmly. This action will be maintained or will continue while the member 3 is in normal or substantially vertical position, as it will be when there is no difference in strain on the conductorat either side of the clamp. In the event of breaking of the conductor or some other unusual occurrence producing an unusual pull at one side of the conductor or the other, the string of insulators, not shown, and the suspension member 3 would swing out of vertical position whereupon the cam projection 10 will either ride off from the clamping member 2 or reach such a position that the pressure upon the member 2 will be relieved if not, entirely eliminated, this depending upon the degree of swinging movement; When the pressure. upon the member 2 is thus decreased the conductor may slip through the clamp. Thisslippage would occur perhaps through a series of clamps along the line until the excessive strain is relieved. Upon return of the insulator string and member 3 to normal or substantially vertical position the clamp will regrip the conductor without necessitating a local manual operation.

A very important feature is the making of the member 2 from sheet material. Clearly, if a thinner material is used the clamping action will be less and the clamp will release at a lighter pull than would be the case if the thickness of the member 2 were to be increased. By this one means it therefore becomes possible to use the clamp in different installations as it is merely necessary to have the interchangeable members 2 of different gauge or thickness.

The shape of the cam extension 10 may be varied if found advisable, depending upon the inclination of the insulator string at which release is desired. No elaborate data is given as to the curvature or other shape as there are so many possibilities and as this is a detail which may well be worked out by actual experimentation.

' From the foregoing description and a study of the drawing it will be seen that I have provided a very simple, inexpensive and easily applied clamp which will, nevertheless, be extreme 1y efficient in action. On account of the fewness of the parts actual manufacture becomes an easy proposition and assembly is greatly facilitated. It is thoughtthat the construction, operation and advantages will be readily apparent to one skilled in the art without further explanation.

While I have shown anddescribed the preferred embodiment of the invention, it should be its understood that the disclosure is merely an ex- "1 emplification of the principles involved as the right is reserved to make all such changes in the details of construction as will widen the field of utility and increase the adaptability of the device provided such changes constitute no departure from the spirit of the invention or the scope of the claims hereunto appended.

Having thus described the invention, I claim: 1. A clamp of the character described comprising an elongated stirrup-like main member having upstanding sides, a relatively movable member located between the sides of said first named member and provided with lugs at its sides, and a suspensionmember pivoted between the sides of said first named member and having a cam projection normally engaging the second named member for eifecting a clamping action on a conductor, said sides having openings receiving said lugs, and the pivotal connection between the first named member and the suspension member being engaged within said openings.

2. A clamp of the character described comprising a relatively stationary clamping member disposable beneath a conductor, a relatively movable clamping member formed as a leaf spring disposable above the conductor within the confines of said relatively stationary clamping member, means for preventing relative longitudinal movement of said members comprising lugs on the movable member engaged within the lower including a bolt engaged within theupper ends or" said openings and reacting against the upper edges thereof.

3. A clamp for supporting a conductor, comprising an elongated channel shaped body hav- 4. A clamp for supporting a conductor, comprising an elongated channel shaped body having the intermediate portion of its sides upwardly extended, and formed with vertically elongated openings with rounded upper ends, a longitua dinally bowed member located within said channel shaped member and having laterally projecting lugs received within the lower portions of said openings, a suspension member provided at its lower end with a cam portion reacting against the center of said clamping member, and

a pivot for said suspension member extending through said openings and reacting against the curved upper ends thereof, said channel shaped member being'of one piece sheet metal construction. t

STEWART L. MOORE, JR. 

